Improvement in devices for hammering saws



C. T. SHOEMAKER.'

Devjces fur Hamm`ering Saws. N0.152,872. Patented1uly7,1874.

JMW/WM v /fwma UNITED STATES PATENT OFFICE..

CHARLES T. SHOEMAKEB, OF PHILADELPHIA, PA., ASSIGNOR TO HENRY DISS- TON, HAMILTON DISSTON, AND ALBERT H. DISSTON, OF SAME PLAGE.

IMPROVEMENT IN DEVICES FOR HAMMERING SAWS.

Specification forming part of Letters Patent No. 152,872, dated July 7, 1874; application filed June 20, 1874.

the head .of which is of the same area and e011-,

formation, and, when the blow is struck, always coincides with the'face of the anvil, as shown in Figure l of the accompanying draw- 1n g.

lt will be proper to remark in the outset that the blades of handsaws are hammered after they have been tempered, ground, and polished, and after the teeth have been eut on the edges. The object of this hammering is to slightly expand the metal at and near the middle of the blade, so as to impart a tension and consequent stiffness to the edges of the same.

The dotted lines in Fig. 2 illustrate the direction of the blows, which are, according to the present practice, imparted by aha-ndhammer of the character shown in Fig. 3, the blade being placed on an anvil, D, theface of which is necessarily larger than that of the hammerhead in order that the workman may perform his duty properly.

Owing to this difference between the hammer and anvil, every blow on the blade has a tendency to bend it; hence the operator must repeatedly reverse the blade, must examine it at frequent intervals, and apply straightedges until it is perfectlyr straight. This oper ation is one demanding much skill and expe rience at the hands of well-paid workmen, and my object is to dispense with much oi' this skilled labor.

In Fi g. l, A is a hammer so driven bypower that it is caused to rise and fall rapidly in suitable guides. This hamlner has a head with a slightly-rounded face, a, and immediately below this face is the similar face b of the anvil. y

I have ascertained by practical tests that if the face oi' the hammer and that of the anvil are of the same extent and conformation, and that if one always coincides with the other when the blow is struck, there will be but little bending of the blade, the latter after it has been subjected to this hammering operation demanding but little skilled labor.

The hammer e and anvil b may be made solid, as shown in Fig. l, or they may consist of plugs or pins adapted to sockets in the hammer-head and anvil-body, and retained therein by set-screws or otherwise, as shown in Fig. 4.

I claim as my invention, and as an improvement in the art of hammering sawblades SubjeetingI them to the action of a powerdriven hammer having a face conforming in shape to and coinciding with that of the anvil, as set forth.

ln testimony whereof I have sighed my name to this specification in the presence of two subscribing witnesses.

O. T. SHOEMAKER.

Vitnesses:

WM. A. STEEL, TnoMAs McILvAIN. 

